Tropical Storm BONNIE

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TROPICAL STORM BONNIE DISCUSSION NUMBER 11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT TUE AUG 10 2004
RECONNAISSANCE AND SATELLITE DATA INDICATE BONNIE HAS MAINTAINED A
TIGHT INNER-CORE WIND FIELD...DESPITE THE RECENT WEAKENING OF THE
CENTRAL CONVECTION. SHIP H3GQ REPORTED 40 KT SOUTHWESTERLY WINDS
ABOUT 40 NMI SOUTH OF THE CENTER AT 18Z. BASED ON THIS REPORT AND A
RECON REPORTED PRESSURE OF 1004 MB...THE INITIAL INTENSITY IS ONLY
BEING DECREASED TO 45 KT.
THE INITIAL MOTION ESTIMATE IS 005/05. THE LAST TWO RECON POSITIONS
INDICATE BONNIE HAS FINALLY MADE THE LONG EXPECTED TURN TO THE
NORTH THROUGH A BREAK IN THE SUBTROPICAL RIDGE. SUBSEQUENT
SATELLITE DATA CONFIRMS THIS MOTION...AND POSSIBLY EVEN A SLIGHT
EAST OF DUE NORTH MOTION. THIS NEW MOTION IS ALREADY TO THE RIGHT
OF THE NHC MODEL GUIDANCE SUITE...SO THE OFFICIAL FORECAST TRACK IS
JUST AN EXTENSION AND UPDATE OF THE PREVIOUS FORECAST TRACK. BONNIE
SHOULD BEGIN TO ACCELERATE SIGNIFICANTLY TO THE NORTHEAST IN 24-30
HOURS AND MAKE LANDFALL IN THE CENTRAL PORTION OF THE FLORIDA
PANHANDLE IN ABOUT 42 HOURS.
AS MENTIONED IN THE PREVIOUS ADVISORIES...BONNIE IS EXPECTED TO
REMAIN A SMALL TROPICAL CYCLONE THROUGHOUT THE PERIOD...WHICH CAN
RESULT IN RAPID INTENSITY FLUCTUATIONS. BONNIE MAY BE GOING THROUGH
ONE OF THOSE TEMPORARY FLUCTUATIONS NOW. THE INTENSITY FORECAST IS
PREDICATED ON DEEP CONVECTION RETURNING WITHIN THE NEXT 6 TO 12
HOURS. ARGUMENTS FOR THUNDERSTORMS REDEVELOPING OVER THE CENTER
LATER TONIGHT OR WEDNESDAY IS...THE RECENT IMPROVEMENT IN THE OUTER
BANDING FEATURES NOTED IN SATELLITE IMAGERY...BONNIE EXPECTED TO
MOVE INTO A WEAK OR EVEN NO SHEAR ENVIRONMENT IN 12-24 HOURS...VERY
WARM SEA-SURFACE TEMPERATURES...AND THE USUAL NOCTURNAL CONVECTIVE
MAXIMUM PERIOD. HOWEVER...BY 36 HOURS...SOUTHWESTERLY UPPER-LEVEL
SHEAR IS EXPECTED TO BEGIN INCREASING...WHICH MAY CAP THE INTENSITY
TREND PRIOR TO LANDFALL. THE OFFICIAL INTENSITY FORECAST IS THE
SAME AS THE PREVIOUS INTENSITY FORECAST AND IS A BLEND OF THE SHIPS
AND GFDL MODEL INTENSITY FORECASTS.
WATCHES FOR PORTIONS OF THE NORTHEASTERN GULF OF MEXICO COASTAL
AREAS MAY BE REQUIRED LATER TONIGHT.
FORECASTER STEWART
FORECAST POSITIONS AND MAX WINDS
INITIAL 10/2100Z 24.7N 90.5W 45 KT
12HR VT 11/0600Z 25.5N 90.4W 55 KT
24HR VT 11/1800Z 26.8N 89.5W 65 KT
36HR VT 12/0600Z 28.5N 87.5W 70 KT
48HR VT 12/1800Z 31.0N 84.0W 50 KT...INLAND
72HR VT 13/1800Z 37.0N 76.5W 30 KT...EXTRATROPICAL
96HR VT 14/1800Z 53.5N 68.5W 30 KT...EXTRATROPICAL
120HR VT 15/1800Z...ABSORBED BY FRONTAL SYSTEM
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